Vulcanizing mold



R. w. BROWN 'A 2,381,395

VULCANIZNG MOLD' Filed July 8, 1943 6 Sheets-Sheet 1 Aug. 7,A 1945.

Aug.' 7, 1945. R. W. BROWN 2,381,395

VULCANI Z ING MOLD Filed July 8, 1943 6 Sheets-Sheet 2 www Aug. 7, 1945. l R. w. BROWN VULCANIZING MOLD v A Filed July 8, 1945 6 Sheets-Sheet 3 ROY W. E QOWN -Aug. 7, 1945. R. w. BROWN VULCANIZING MOLD Filed July 8, 1943 6` Sheets-Sheet 4 SECTION AT '1J-'g FIG 8 Aug. 7, 19.45.v R. w. BROWN I VULCANIZING MOLD zov w. BROWN Filed July s, 1,945

Aug.: l7, 1945.

RL w. BROWN VULCANI ZING MOLD Filed July 8, 1945 6 sheets-sheet e Patented Aug. 7, 1945 Y Y' vunfegrmzmermomr y corporation of"`0hi,

Thisrinvention relates: to f vulcanizing molds; f andf -m orel "especially: it'f relatesxtoi molding appara f tusfffor."vulcanizingf'endlessf articles ofrelatively` long* lengths which articles4 'ares` interiorlyv 'reinefoncedwa. ,5

v YThefnfrentirxis'fof'fprimary utilityfinlth'e:mana'. uffaoture"ofe` endlessA treads or` traeksffor' track` laying? vleliielesf,l suoi'ry as: the I vehicle`V known'l as a half-trac?" y Sucli`- treads.f ontracks; .differ froma ,thefytreads or` tracks ofcombat'veliicles knowneasif 10-V tankstim that theyrv are unitaryf'endlessr'structures'instead of"P articulated; g and?i aref longitudi'# nall-wfiexibleandfinextensible. Tothisfend, tracks*A ofitlre ohanactermentioned; `Whrohr-consistwessen@ tiallyf.- oicrubber orirubberdikercompositi-on; *are* 15 interiorlyfreinforced-'fwitrrraf plurality=- off comzolu-l l tions of.;1'1eavyrwire-or-wire lcable;m arxdfit,r is Vofc. pri-1 y mary vimportancethat saideonrolutionsf bei" of- Kuniformf; strength -liand length.' inf order that: allmaypbear; an equal share ora theloadfduring serv- 20 ice.=wAccording11y, during theffabricati'onof the: track: unitsglfthe convolutionstof reinforcing ma-n terialeiare; appliedmnderconstant 1uniform-tensi on; andithevrespective -endsvfot the:materialgareffsuitL if n ablya-nohored in thefunits sor-thatthel convolu-#I tonsgdo .not eontraetmW-t'xen severed fromlthe-supa plyyspool of-re-inforoingmaterialf: /Itfisoneaofthechief objects of this ,inventionL-to provide,nvzulcanq izing and moldingvapparatus for articles. or the character described'whereinz-the reinforcing ele,-`AV mentsifare2 maintained `underztllei-r, in'li'.ial:ur-iiform,v tension (untilfthe-time that.. vul@ anizatiomor their.l ruhbervicompositioniis completed.: f

Heretoforaie hasfbren` armeniacompieteiygtb:

vuleanize. rubber articles1 off long .lengtib aty one@ 35.

I.t isfevssentialsthat said@ embedded ymetal ele-ai 55 ments-beaeourately positioned' softlatftlieartieu lated*` driving "zrrernbenf may" be" attacl'ieclt i'flfiereto; .ticoo'rclirrglyv it'is 4an'oth'ercobject? off' the' inventionv tof#4 provide moldngi-'andY 'wleanizin'g apparatus.'- adapted-properlytofpositiorrembe'dded metall vele 'While the` latter" isrbeing molded? andvuloanize'd' under'pressure. l'

- "Further objects ofthefinvention are toaehi'eve"V superior qualityirrmlded `and. l vulcanized articles `oflftlre character:mentioned; to provide -f'r m'oli 5 ingfendlss yartieles 'of "relatWely-longv 'length' Wlile l they' are maintained" in" true'y circular form'; "to" provid-ee forj'the' manufacture' offsucli: articles at'l reduced' 'costi'- and- `Itojprov'cle an improved*v-ul ':ar1'` tieles: Other'objects-:will be: manifestfas tire'-n cieorfoperative?condition:Y

Fig. 2,-isa side^elvation thereof;

therefrom;

Franse' sie@ elevation-'off the scruerurejmthef con ditionshowwinffig :3

tiforrinzitsrfullyopen'condition; H

Fig: vf-isa section orrftlrie line -SioiFigqlj' Figi 'TrisA ar fragmentary plan'view offtloe molti' segm'ents ofthey vu1canifzingf'Triolet;A on"r 'a' larger" scale= and" infv closed orv operative position; and the Work: therein; 'parts'i being.brokenlv away andiio" 1-1 isy a'Section5,onfalargerfsca1e, 'oir the y"lrre'fl |':-I f'iof-Fi'gf'7;U l 'Eigy 12::is;a`= section' of-A aneendles'f ring; anda segmental; ringfjoperatively" associated? therewith',I wliioh :ringssupportthe Work during: fabricationu thereof and While the work is in the Vulcanizi'ng "Fier: 1131'is1faf'sid'e elevation' of the fnishedworkfasfit' appears 'when' mounted"`fr"use upon a ve I hielo; p'orti'onsnffthe latter 'beirigy shown broken lint-2ST and f Fig. v14 is a fragmentary sectional perspective view of the finished work.

Referring to the drawings, particularly Figs. 1

to 5 thereof, there is shown a vulcanizing mold y comprising a circular base plate I5 upon which is mounted a circumferential series of radially arranged bearing brackets lof substantially U- shape. Saidbrackets are shown as eight in number, and are designated I6 and I1 alternately throughout the series. The leg portions of said bearing brackets extend upwardly, and the bearing portions of the brackets are at the tops of the respective legs thereof, the two bearings of each bracket being in alignment radially of the structure. Supported by said brackets upon the medial regions thereof, somewhat below their bearing portions, is a fiat, annular, bed plate I8.

region I1a on the inner end of the bracket I1. Said region I1a has a horizontal bore 34 extending transversely therethrough near the top thereof, which bore intersects the bore 33. A pin or other suitable tool (not shown) may be inserted through the bore 34 to constitute a support for the stem 32, and elementsY carried thereby, when said stemis in elevated position as shown in Fig. 4. Mounted in each bearing head 3| is an internally threaded bushing 35, and threaded through the latter is a screw 36, said screw and 1 bushing being identical with the screws 21 and bushings 26 hereinbefore described. Swivelled ,1f/on the head 'formed on the outer end of the .5,

screwv36 is a longitudinally arcuate mold segment that is designated as a whole by the numeral 31.

The mold segments 31 are arranged in alter- 'Ihe outermost bearing portions of the brackets each screw 2| is formed with a rounded head 23, Figs. 'Tand 10, and swivelled on said` head is a longitudinally arcuate mold segment that is designated as a whole by the numeral 24, vsaid mold segment resting upon the bed plate I8. The

mold segments are radially movable by means'of the screws 2| and in their innermost positions they abut each other end to end and define a circular mold structure that is adapted to exert molding pressure upon the periphery of a'c'ircular work-piece, as shown in Figsl, 2 and "7, the work-engaging face of each mold segment being on the concave side thereof. I'he mold segments are moved radially outwardly to the inoperative position shown in Fig. 5 when iinished work is to be removed from the4 mold'and an vunvulcanized work unit mounted therein.

The innermost bearing portions of the brackets I6 are substantially identical with the outermost.

bearing portions thereof. Thus each of said innermost bearing portions comprises an internally threaded bushing 26, and threaded into ,the latter is a screw 21. The Vradially innermost endA of each fscrew 21 is formed with a hexagonal wrench socket (not shown), and the opposite end of thescrew is formed with a rounded head 28, Fig. 10, inthe same manner as the screws 2| `previously described. Swiveled on `the screw heads 28 are respective longitudinally arcuate mold segments, eachdesignated as awhole by the numeral 29, said mold segments resting upon thebed plate I8. The mold segments 29' are alternate segments of a circular mold structure that consists `of key segments and intermediate segments, the segments 29 being intermediate segments. The `mold segments 29 are adapted to exert molding pressure upon' the inner circumference zofv a circular Work-unit, as lshown in;Figs. 1, 2 and 7, the work-engagingsface off each.mold segment being on the convex side thereof. i

The innermost bearing portionsof the brackets.:

I1 differ `from the brackets I6 in thatthey; are

provided with respective vertically movable bear ing `heads 3|, each-of which headis formed with a depending stem or post 32` that isi'slidablyy received in avertical bore 33 in an enlarged 30 mentsare in their radially outermost positions wherein they operatively engage the work unit. Thus the angular arrangement of the end faces of the segments is such that the intermediate segments 29 cannot be retracted or movedradially inwardly awayfrom the work-unit until after the key segments 31 have been retracted. After the key segments have been'moved to their radially innermost positions there still is not sufficient space for the intermediate segments 29 Vto be retracted sufficiently to clear the work-V unit, as will be apparent upon reference to Fig. 3. It is for this reason that thekey segments are carried by vertically movable bearing heads 3| whereby the said key' sections 'may be elevated to a plane above the intermediate segments, as shown in- Fig. 4, thereby enabling lthe intermediate segments to be moved to their radially innermost limits, as shown lin'lig. 5.

AThe `elevating of the key'segments 31v from their lowered and retracted position to the elev'ated position shown inl Figs 3, 4 and 5 is effected by any suitable overhead hoisting mechanism (not shown), there being an aperturedplate or eye 39 secured' tothe concave side of each of said .screw 36 thereto, for engagement with suitable fhicle elements Aas shown 'consist vof hooks-0f said hoisting mechanism.

Referring now toy Figs. 13and14 of the drawings, there is shown an endless track or tread 4I such as is molded and vulcanized in the apparatus of the invention. In Fig. 13 the track 4I is shown as it appears when mounted for use upon a vehicle, the elements of the latter that'engage the `tr.'a.ck`l:\eing shown in broken lines.. Said vesprocket wheels 42, 42, one or both of which are power driven, and a series of 'bogie wheels 43, 43. In the finished track metal clips are attached at spaced points longitudinally of the track and cro- -ject inwardly from the inner sidethereof sn as `showing thereof is necessary. However, the inner f ylimit of the seriesof v clips is indicated bythe broken line 44, Fig. 13.

L-vA'sni's best-shown mrtg, '14,` the track '41. com- `prisesr two` identical, parallel, lendless track elements-Ma, v4|a, that vare arranged side bysidein spaced vrelation to'each other. `Said track elementsfarecomposed essentially ofy tough abrasion-resisting,A vulcanized rubberl composition, either-natural or synthetic, andare reinforced by a plurality of circumferentially extending convolutions of metal Wire or cable 46, 46. Foratytaching the driving clips aforementioned to the track, ,the latter is provided with a circumferential-` eeresotmetal inserts, 4.1, 41 that are dispose transversely of. the track and are embedded vwithin. .the,structures of thel respective elements ,41a thereof. The, inserts 4 1 span the space between said 4track elements 4|a and serve to maintainthe latter in properlyspaced apartrelation. The opposite. ends ofthe inserts41 project somein Figs.' 7 and 1'1. Thereafter the rubber compositionv of the track elements 4|a is applied over the Wires 46 and inserts 41, the fabrication being finished when a sufficient thickness of .rubber is obtained.

Thereafter the unvulcanized track, together with the endless ring 50 and ring segments 5| attached thereto, are removed as a unit from the rotatable drum or support upon which the track was built, and mounted in the vulcanizing mold h ereinbefore described while the outer and inner mold,` segments thereof are in the fully retracted positions shown in Fig. 5. When the work .is being mounted in the mold it is essential .that thering structure 50, be determinately arranged angularly with relation to the mold i segments, and to this end the said ring structure is formed with a-circumferential series of radial `whatfrom the respective lateral-faces or margins formedonhtheir confrontingfaces,` with correspondingutransverse groovesrin which the-wires or cables 46 are received, the elements'41a of the ,espectiveinserts being clamped together so as Ig/ litly to gripA-Asaidcablesw themfabrication rof the unvulcanizedtrack 4| ,'an annu lar,POWer driven support or drum (not showngffisprovided, and removably mountable upon saidsupportis anl endless metal ring 56,` The, peripheral face of said ring is transversely' stepped or shouldered, andmounted l upon said peripheral face Vis a circumferential series of lfoirigitudinally arcuate ring segments 5| yarranged 'in end t end relation, the ,confrontingl surfaces f'the e'lless lring and the ring segments 5| being rcoriplementally shaped..y Cap screws 52, Fig. v12,` extending throughv ,the segments 5| and jt'hreafded''into"the ring 56 maintain the ring `and "segments iniassembled relation. At spacedv points kcircumferentially of the assembly the segments -5|-\ areftransyverselyVV slotted attheir periphery to receive'the inserts 41;v 1 Duringfthe rststeps-of building a track 4|, the inserts 41Lare notl mounted upon the ring'structure. Thislienables-=p1ies of unvulcanized rubber composition to be assembled on'the supporting structure,atgoppositesides of the ring segments bores 58, and receivable in said bores,from opposite ends thereof, are ydowels 59 secured to the inner mold segments 29, 31, and the outer mold ywithout hindrance; ,After the proper number Y of A"rubber plies are as sembledthe innermost ele- .ments 41avlof the moldlinserts are mounted upon the ringv segments 5| and `temporarily secured thereto", 'theftransverse grooves of said inserts vfacing'-outwardly; 'The'next step ist'o applyfthe wires or cables 46, and these cables preferably are "coveredvo'r insulatedV with rubber compositionl 'that ispartly vulcanized; "The wires 46 are ap- Jpliedcircumferentially of thetrack under unif-form determined tension, the respective ends of `thenavires;briconvolutions'thereof, being suitably -anchor'ed ltoafinsert "elements 41a so as to vretain said-wires"under tension.'I After "the Wires 46 are 'in1-place*'-th'ef outerj'insert "elements 41a` are mount'ed over the inner insert` elements, and se- `cured tov thev latter-"and to the ring assembly by respective screws 54 that extend through the in- `Nserts andthe ring segments 5| and are'threaded tfinto shouldered nuts 55",'that are receivedi'n revspective counterbored' radial Iar'nertures 56 inthe 'endless ring^50,and th ringsegments, as )Show/rn segments 24, said dowels being located substantially centrally of the confronting molding faces of the two series of moldvsegments. .The confronting faces of the respective series of mold segments are formed with molding cavities forl in which the radially inner portion of the ring .f-

structure 50, 5| is received, and the outer series of mold segments is formed with ar narrower and 'shallower groove 6| in which the peripheral portion of the segmental ring 5| is received. `The 'medial' region of the segmental ring 5|' centrally divides the molding cavity in the mold, and thus ,constitutes a part of the molding surface that vshapes the two elements 41a, of the work-unit.

The *arrangementl enables the work to be positioned centrally of the mold in avertical direction, the dowels 59 also enabling the work to be properly positioned angularly of the mold.

The respectiveinner lmold segments 29, 31 `are formed'vvithr radial bores at the respective ends thereof, andtheouter mold segments 24 are formed with similar bores. Furthermore the ring structure 5D, 5| is formed with a circumferential series of radial bores, and when a work unit is in the .mold and the mold segments are moved toward each otherto apply molding pressure to the Work unit, said bores are in axial alignment and receive bolts 62; 62,'Figs. 7 and 9, for a purpose which presently will be apparent. The *outerv moldsegments 24 comprise steam chambers 63, and the inner mold segments comprise steam `chambers 64, which chambers, when lled'with steam, supply the heat for vulcanizing the rubber compositionA of the Work unit in the mold. Suitable exible piping (not shown) is provided for rvcirculating steam through the several mold segfrnentsLgas is Well understood by those familiar .with this art.

After the `work unithas-been mounted within v'the mold as previously described, the ,mold is closed upon the work. n In this operation, the first step is to A,move Athe intermediate mold segments 29` outwardlyinto engagement. with .the `inner circumference/,of thevwork. Then the key segments k31. may be lowered from the elevated posi- -1 tio'rfin shown in ligfJ-L to a position-,in the same planeas saidintermedi'ate segments29, The key engagement with the work, in which positionthey are in end-to-end relation with the intermediate segments. Finally, the segments 24 of `the outer series `are moved radially inwardly into engagement with the work. It will be understood that radial movement of'the mold segmentsfis effected by turning of the screws 2l, 2-'l and 36 by means' of a wrench inserted into the socket in the outer end of the respective screws. are turned in succession, a power-driven wrench preferably being employed for the purpose. Owing to the 'stiffnessof the unvulcanized rubber of the Awork unit, it is not possible immediately to move the mold segments to their ultimate molding positions.` In practice, however, steam` is constantly circulatingthrough.- the mold segments so that they are inheated condition when applied to the work. This causes the -rubber composition of the work rapidlyrto soften and become flowable, so` that a subsequent `turning .1' of the screws Ztl, 21 and 35.will move the moldy segments to their ultimate molding positions wherein the work .is completely enclosed, the mold then appearing as shown .in Fig. 1 of the drawings. At this time the bolts 62 `may be applied to the moldso as more securely to hold n the mold segments in engagement with the work.

are removed, which enables the endless ring 5l)l to be removed yfrom the ser-ies of ring segments 5|the latter then being removable. individually.

From the foregoingit will be seen that the mold is so constructed and arranged :that the wires 46 in the article aremaintained.underten- -sion from the time they are appliednntil `the time that vulcanizationis completed. Further-Y more, the metal inserts are held in proper posi-L tionat alltimes notwithstandinglmolding presi segments arranged about the same axis, the two The said screws `sure applied to the rubber structures, and vulcanization is effected concurrently throughout the entire length of the endless track.` Because the track is molded while in true circular form', itv will not be subjected to as severe exing stresses during use as would be the. case if it werevulcanized in longitudinally flat increments.v Thus the invention produces an article of superior quality, i and achieves the other advantages set out in the foregoing statement of objects.

Modification may be resorted to without departing from the spirit of the invention, or the scope thereof as defined by the appended claims.

What is claimedis: l l. l

l. A vulcanizing mold` of the" character described comprising the combination of an outer circumferential ser-ies of mold segmentsarranged about a vertical axis, an inner circumferential series of mold segments arranged about the same axis, the two series being in the same plane in the operative condition of the mold, means for individually moving the mold segments of each series in a radial direction, and means for moving some of the lsegments of the'inner series out'r cal axis, an inner-'circumferential series of mold:

series being in the same plane' in the operative `condition of the mold, said inner series comprising` a plurality of key segments and a pluralityof intermediate segments, means for individually moving the mold segments of both series in a radial direction to and from work-en.-

gagingfposition, and means for elevating the l key segments of the inner series to a position above the plane of other segments.

3.' A mold of the character described comprising a bed plate, an outer circumferential series of arcuate mold segments supported thereon and arranged about a vertical axis, an inner circumferential `series of arcuate mold segments supported on said bed plate and arranged about -the aforesaid vertical axis, the two series being in the `same plane in the operative condition of the mold, said inner series comprising a plurality of key Lsegments and a yplurality of intermediate segments, respective screw elements to which said segments are swivelled adapted to move said segments in a radial direction to and from workengaging position, bearing members for said screw elements,` and means for positioning the bearing members of the key segments at an elevated position whereby the key segments may be positioned above the plane of the other segments.

4. A combination as defined in claim 3 including respective posts upon which` the bearing members of the key segments are mounted, and respective brackets in which said posts are slidably mounted for vertical movement.

5. A mold ofthe character described comprising two concentric series of arcuatel mold segments, the segments of one series being arranged in opposition to the respective segments of the other series, all of said segments being disposed in the same horizontal plane in the closed con.- dition of the mold, the confronting faces of the opposedsegments being formed with molding surfaces adapted to shape an annular article positioned therebetween, individual means for moving the respective segments of each series vradially to open and close the mold, and means for positioning some of the segments of the inner series out of the plane of the remainder of the segments to enable maximum inward radial movement of all the inner segments during opening of the mold.

6. A combination as defined in claim 5 in which the inner series of mold segments comprises key segments and intermediate segments, and vertically adjustable supports for the key segments renabling them to be elevated to a position above the plane of the other segments of the mold.

7. A mold of the character described comprising two concentric series of arcuate mold segments, means for moving the segments of each series radially,` from and toward the other series,

to open and close the mold, the confronting arcuate faces of the opposed segments being formed lwith molding cavities adapted to receive and shape an annular article positioned therebetween. and a ring-shaped structure positionable interiorly of the mold between the two series of segments and in operative engagement with y the segments of each series to divide the molding cavity of the meld into two vparallel separate annular molding portions, parts of said ring structure constituting molding surfaces for shaping portions of said article.

8. A mold of the character described comprising two concentric series of arcuate mold segments, means `:for moving the respective segments of each series radially from and toward the other, to open and close the mold, the confronting faces of theopposed segments being formed with molding surfaces adapted partly to shape an annular article positioned therebetween, said confronting faces also formed Withr respective `longitudinally extending grooves in which a molding element is receivable, anda ring-shaped structure positionable between the two series of segments and partly seatable in said grooves,

portions of said ring structure constituting molding surfaces for shaping portions of said article, 15

said ring-shaped structure being composed of separable parts to enable it to be disengaged from the moldedarticle.

9. A combination as dened in claim 8 Where` 

